}
  }

  // Returned from removeAt() to iterator.remove()
  static class MoveDesc<E> {
    final E toTrickle;
    final E replaced;

    MoveDesc(E toTrickle, E replaced) {
      this.toTrickle = toTrickle;
      this.replaced = replaced;
    }
  }

  /** Removes and returns the value at {@code index}. */
  private E removeAndGet(int index) {
    E value = elementData(index);

        if (existingCounter.compareAndSet(oldValue, newValue)) {
          if (newValue == 0) {
            // Just CASed to 0; remove the entry to clean up the map. If the removal fails,
            // another thread has already replaced it with a new counter, which is fine.
            countMap.remove(element, existingCounter);
          }
          return oldValue;
        }
      } else {
        return 0;
      }
    }
  }

      alertListenerIfPresent(key, oldValue, RemovalCause.REPLACED);
      put(key, newValue);
      return true;
    }
    return false;
  }

  @Override
  public V replace(K key, V value) {
    V currentValue = get(key);
    if (currentValue != null) {
      alertListenerIfPresent(key, currentValue, RemovalCause.REPLACED);
      return put(key, value);
    }
    return null;
  }

        if (oldValue == 0L) {
          // don't compareAndSet a zero
          if (map.replace(key, atomic, new AtomicLong(delta))) {
            return delta;
          }
          // atomic replaced
          continue outer;
        }

        long newValue = oldValue + delta;
        if (atomic.compareAndSet(oldValue, newValue)) {
          return newValue;
        }
        // value changed

   * in turn invoke arbitrary code it is not safe to call while holding a lock.
   */
  final void interruptTask() {
    // Since the Thread is replaced by DONE before run() invokes listeners or returns, if we succeed
    // in this CAS, there's no risk of interrupting the wrong thread or interrupting a thread that
    // isn't currently executing this task.

    // If duplicates are allowed, this map will track the last value for each duplicated key.
    // A second pass will retain only the first entry for that key, but with this last value. The
    // value will then be replaced by null, signaling that later entries with the same key should
    // be deleted.
    Map<K, @Nullable V> duplicates = null;
    int dupCount = 0;
    for (int i = 0; i < n; i++) {

    map.put(one, three);
    assertNotified(listener, one, two, RemovalCause.REPLACED);

    Map<Object, Object> newMap = ImmutableMap.of(one, four);
    map.putAll(newMap);
    assertNotified(listener, one, three, RemovalCause.REPLACED);

    map.replace(one, five);
    assertNotified(listener, one, four, RemovalCause.REPLACED);

    map.replace(one, five, six);

    map.put(one, three);
    assertNotified(listener, one, two, RemovalCause.REPLACED);

    Map<Object, Object> newMap = ImmutableMap.of(one, four);
    map.putAll(newMap);
    assertNotified(listener, one, three, RemovalCause.REPLACED);

    map.replace(one, five);
    assertNotified(listener, one, four, RemovalCause.REPLACED);

    map.replace(one, five, six);

        if (existingCounter.compareAndSet(oldValue, newValue)) {
          if (newValue == 0) {
            // Just CASed to 0; remove the entry to clean up the map. If the removal fails,
            // another thread has already replaced it with a new counter, which is fine.
            countMap.remove(element, existingCounter);
          }
          return oldValue;
        }
      } else {
        return 0;
      }
    }
  }

   * generated by applying {@code function} to the elements of {@code fromSpliterator}. (If {@code
   * function} returns {@code null} for an input, it is replaced with an empty stream.)
   */
  static <InElementT extends @Nullable Object> Spliterator.OfInt flatMapToInt(
      Spliterator<InElementT> fromSpliterator,